You have already availed credit so nothing wrong at your side. You have invoice copy to prove that you did not claim wrong input credit.
However, you cannot do anything now at your side. It is best to preserve copy of invoice with you which you received.
However if you invoices with changed dates, then legally you need to claim input in December GSTR-3B and reverse one which was claimed in November along with interest for one month at 24% PA.